# CVE-2026-70470: Flowise: Pyodide validator Unicode homoglyph bypass leads to RCE

> Attackers can bypass Python code validation using Unicode homoglyphs to execute arbitrary code on the host via Pyodide interop.

- **Severity:** Critical 9.5 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Aug 2026
- **Updated:** 4 Aug 2026
- **Also known as:** GHSA-52fh-8v99-63c2

## What is CVE-2026-70470?

CVE-2026-70470 is a critical code injection vulnerability in Flowiseai Flowise, published on 4 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.3, Flowise validatePythonCodeForDataFrame in packages/components/src/pythonCodeValidator.ts can be bypassed with Unicode homoglyph identifiers, allowing arbitrary Python execution inside Pyodide and full OS command execution on the Flowise host via Pyodide js module interop. The validator gates pyodide.runPythonAsync in packages/components/nodes/agents/CSVAgent/CSVAgent.ts and packages/components/nodes/agents/AirtableAgent/AirtableAgent.ts with an ASCII word-boundary blacklist. JavaScript regex word boundaries are ASCII-only, while Python 3 NFKC-normalizes identifiers at parse time, so homoglyph forms such as __cl𝐚ss__, __subcl𝐚sses__, __b𝐚se__, and __b𝐮iltins__ bypass the blacklist and are parsed as their ASCII equivalents. This issue is fixed in version 3.1.3.

Weakness: CWE-184 (Incomplete List of Disallowed Inputs)

## Which versions are affected by CVE-2026-70470?

4 open source packages ship an affected version, including flowise and flowise-components. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `flowise` | npm | All versions | 3.1.3 |
| `flowise` | npm | All versions | 3.1.3 |
| `flowise-components` | npm | All versions | 3.1.3 |
| `flowise-components` | npm | All versions | 3.1.3 |

Products: Flowiseai Flowise.

## How do I fix CVE-2026-70470?

Upgrade flowise to 3.1.3 or later.

## Is CVE-2026-70470 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-70470 exists.

## Other vulnerabilities in Flowiseai Flowise

- [CVE-2025-71338](https://insights.sbomify.com/CVE-2025-71338/): Flowise through 2.2.7 - Arbitrary File Write to Remote Code Execution via document-store API (critical 10.0)
- [CVE-2026-40933](https://insights.sbomify.com/CVE-2026-40933/): Flowise: Authenticated RCE Via MCP Adapters (critical 10.0)
- [CVE-2025-61913](https://insights.sbomify.com/CVE-2025-61913/): Flowise is vulnerable to arbitrary file read, arbitrary file write (critical 10.0)
- [CVE-2025-59528](https://insights.sbomify.com/CVE-2025-59528/): Flowise has Remote Code Execution vulnerability (critical 10.0)
- [CVE-2026-52098](https://insights.sbomify.com/CVE-2026-52098/): Code injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-70470 and fix it if it is affected.

What it is: CVE-2026-70470 is a critical code injection vulnerability in Flowiseai Flowise, published on 4 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-70470 exists.

Affected packages and fixed versions:
- flowise (npm): affected all versions; fixed in 3.1.3
- flowise (npm): affected all versions; fixed in 3.1.3
- flowise-components (npm): affected all versions; fixed in 3.1.3
- flowise-components (npm): affected all versions; fixed in 3.1.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-70470/ (Markdown: https://insights.sbomify.com/CVE-2026-70470/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-70470
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-70470
- OSV: https://osv.dev/vulnerability/CVE-2026-70470

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-70470/
Summaries are generated and may contain mistakes; the official description above is the record.